Particle discrimination capabilities of lanthanum halide scintillators

Abstract In the last few decades, lanthanum halide scintillators such as LaBr 3 (Ce), LaBr 3 (Ce+Sr) and LaCl 3 (Ce) have been extensively used for gamma ray spectroscopy measurements. They offer excellent energy resolution (about 3%–4% at 662 keV) and fast scintillation time, allowing high counting rate measurements. These scintillators find applications in many research fields such as nuclear physics, astrophysics, nuclear fusion and nuclear medicine. More recently, thanks to the exploitation of the n- 35 Cl nuclear reaction channel, LaCl 3 (Ce) crystals have been used as neutron spectrometers. This opened up the opportunity to explore pulse shape discrimination algorithms for enabling the neutron/gamma discrimination. In this work, an innovative algorithm for particle discrimination applied to lanthanum halide scintillators is presented. The effectiveness of the algorithm has been demonstrated first on the intrinsic radioactivity measurement of the crystals, which is characterized by gamma ray emissions from 138 La decay and alpha decays due to actinides contamination, and then with fast neutrons. The particle discrimination feature allows for a better description of the intrinsic activity of the crystal and improved background suppression when performing gamma ray spectroscopy measurements in low cross-section measurements or in a mixed gamma-neutron radiation field.